The present invention relates to abrasive particle blasting and in particular abrasive particle blasting by recycling of steel grit.
Abrasive blasting of steel structures, such as highway bridges, is a necessary step in maintenance of structures. In particular, abrasive blasting is a precursor to repainting of steel structures. One particular problem encountered with structures such as bridges is that the past painting history of the structure typically will include a lead-based paint. Abrasive blasting tends to liberate lead dust from such structures. Lead dust however, is considered quite toxic and is increasingly regulated. One approach to controlling environmental contamination from the lead dust resulting from abrasive blasting is to recover all of the dust resulting from an abrasive blasting procedure. If the abrasive blasting is accomplished using sand particles, the lead dust ends up mixed with the sand particles. This results in an undesirably high quantity of hazardous waste for subsequent disposal. A more desirable alternative is to employ a reusable steel abrasive particle. Steel is denser than sand and therefore more effectively retains blasting energy.
In the past, devices for accomplishing the entire process have typically been mounted on separate vehicles. That is, one vehicle may carry the blasting equipment, a second vehicle may carry the vacuum equipment, and a third vehicle may carry a compressor for providing high energy air.